Prevalence of Regulatory T-Cell Subtypes in Preeclampsia.

PROBLEM The prevalence of regulatory T cells (Tregs) is lower in preeclampsia (PE) compared with healthy pregnancy (HP). However, the proportion of recently described Treg subtypes has not been investigated. METHOD Peripheral blood samples of 19 PE and 21 HP women in the third trimester were evaluated using flow cytometry for the prevalence of activated T cells and naive, effector, thymic, extrathymic, and exhausted Tregs. RESULTS The prevalence of activated T cells and exhausted Tregs was higher in PE than in HP. The prevalence of the functionally most active effector Tregs is decreased, while naive Tregs appear to be unaffected in PE compared with HP. No difference was detected between Tregs according to their origin (thymic or extrathymic). CONCLUSION The combination of lower effector Treg and higher exhausted Treg prevalence may account for the decrease in the functionality of Tregs in PE.